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采用热熔挤出法制备地塞米松-聚乳酸-羟基乙酸共聚物(PLGA)植入剂,并通过体外释放度、质量损失、相对分子质量变化、差示扫描量热法(DSC)和扫描电镜等探究甘露醇对地塞米松植入剂释放的影响。DSC结果表明,处方中的甘露醇经热熔挤出后依然以晶体的形式存在于体系中,并且在释放过程中,甘露醇含量越高,其从体系中释放的速率越快。体外释放结果显示添加甘露醇可以消除地塞米松PLGA植入剂体外释放的迟滞期,并延长释放周期。对含5%、10%和15%甘露醇处方的体外释放数据用零级释放模型进行拟合,相关系数r分别为0.991、0.997、0.980。质量损失、相对分子质量变化和扫描电镜的分析结果表明,随着甘露醇含量的增加,PLGA的降解速率降低,而这主要是由于PLGA的自身催化诱导降解效应受到抑制造成的。此外,添加甘露醇能在释放和制备过程中形成孔道,从而改变药物的释放和传质机制。
Dexamethasone-PLA-PLGA implants were prepared by hot-melt extrusion. The dexamethasone-PLGA implants were prepared by in vitro release, mass loss, relative molecular mass change, Electron microscopy to explore the mannitol release of dexamethasone implants. The DSC results showed that the mannitol in the formulation was still in the form of crystals after hot melt extrusion, and the higher the mannitol content during release, the faster the rate of release from the system. The results of in vitro release showed that adding mannitol can eliminate the delaying period of in vitro release of dexamethasone PLGA implants and prolong the release period. The in vitro release data of 5%, 10% and 15% mannitol prescriptions were fitted by the zero-order release model with correlation coefficients r of 0.991, 0.997 and 0.980, respectively. The results of mass loss, relative molecular mass and scanning electron microscopy showed that the degradation rate of PLGA decreased with the increase of mannitol content, which was mainly attributed to the inhibition of self-catalyzed degradation of PLGA. In addition, the addition of mannitol can form pores during release and preparation, thereby changing the drug release and mass transfer mechanisms.